Step 3.7 Flash vs Solar Pro 3
Step 3.7 Flash leads Solar Pro 3 on the Artificial Analysis Intelligence Index, 19.5 to 7.8, and Solar Pro 3 costs 1.9x less per output token ($0.60 vs $1.15 per million). Updated October 21, 2026; 9 benchmarks have a result for both.
Step 3.7 Flash or Solar Pro 3: which to pick
Neither model has a coding score yet, so the two cannot be ranked on coding.
Pick Step 3.7 Flash for a larger context window (262K against 131K tokens) and work measured by IFBench, where it leads.
- Shared results
- 9
- Step 3.7 Flash only
- 9
- Solar Pro 3 only
- 1
- Like-for-like categories
- 5 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
No call
Neither has a coding score yet.
One side not measured
Intelligence
AA Intelligence Index
Step 3.7 Flash
Step 3.7 Flash leads, 19.5 against 7.8.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Solar Pro 3 has a AA Agentic Index result, 1.4.
Directional only
Web design
Design Arena: websites
No call
Only Step 3.7 Flash has a Design Arena: websites result, 1196.
Directional only
Long documents
Listed context window
Step 3.7 Flash
Step 3.7 Flash takes 262K tokens against 131K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Solar Pro 3
Step 3.7 Flash $0.0008, Solar Pro 3 $0.0004 per turn.
List prices
At a glance
- Coding index
- Step 3.7 Flash not benchmarked, Solar Pro 3 not benchmarked.
- Widest category
- Coding, 23.3 points apart on average over 3 shared benchmarks.
- Widest single gap
- Long context reasoning (AA-LCR): Step 3.7 Flash 73.7% against Solar Pro 3 32.3%, 41.3 points apart on a 0 to 100 scale.
- Output price
- Step 3.7 Flash $1.15 against Solar Pro 3 $0.60 per million output tokens, 1.9x apart.
- Context window
- Step 3.7 Flash takes 262K tokens, Solar Pro 3 131K.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | Step 3.7 Flash | Bars | Solar Pro 3 | Ties |
|---|---|---|---|---|
| Coding | 3 | 0 | ||
| Intelligence | 1 | 0 | ||
| Agentic work | 1 | 0 | ||
| Reasoning | 2 | 0 | ||
| General | 1 | 1 | ||
| All shared boards | 8 | 1 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index30
| Benchmark | Step 3.7 Flash | Solar Pro 3 | Leader |
|---|---|---|---|
| AA Coding Index | 39.6 | 16.2 | Step 3.7 Flash |
| SciCode | 43.9% | 25.5% | Step 3.7 Flash |
| Terminal-Bench Hard (Artificial Analysis run) | 35.6% | 7.6% | Step 3.7 Flash |
| ALE-Bench | 694.1 | Not measured | Only Step 3.7 Flash measured |
| Neither model has a result on the other 35 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Step 3.7 Flash | Solar Pro 3 | Leader |
|---|---|---|---|
| AA Intelligence Index | 19.5 | 7.8 | Step 3.7 Flash |
| Neither model has a result on the other 1 board here | |||
Agentic workLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Step 3.7 Flash | Solar Pro 3 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 1.4 | Only Solar Pro 3 measured |
| τ²-Bench Telecom | 98.5% | 86.3% | Step 3.7 Flash |
| Neither model has a result on the other 39 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Step 3.7 Flash | Solar Pro 3 | Leader |
|---|---|---|---|
| GPQA Diamond (Artificial Analysis run) | 80.9% | 72.4% | Step 3.7 Flash |
| Humanity's Last Exam (Artificial Analysis run) | 21.4% | 10.3% | Step 3.7 Flash |
| Neither model has a result on the other 20 boards here | |||
MathNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Step 3.7 Flash | Solar Pro 3 | Leader |
|---|---|---|---|
| Neither model has a result on 13 boards here | |||
KnowledgeNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Step 3.7 Flash | Solar Pro 3 | Leader |
|---|---|---|---|
| Neither model has a result on 18 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
| Benchmark | Step 3.7 Flash | Solar Pro 3 | Leader |
|---|---|---|---|
| Design Arena: websites | 1196 | Not measured | Only Step 3.7 Flash measured |
| Design Arena: UI components | 1179 | Not measured | Only Step 3.7 Flash measured |
| Design Arena: game dev | 1158 | Not measured | Only Step 3.7 Flash measured |
| Design Arena: data viz | 1172 | Not measured | Only Step 3.7 Flash measured |
| Design Arena: 3D | 1129 | Not measured | Only Step 3.7 Flash measured |
| Design Arena: all code categories | 1182 | Not measured | Only Step 3.7 Flash measured |
| Design Arena: SVG | 1085 | Not measured | Only Step 3.7 Flash measured |
| Design Arena: ASCII art | 1152 | Not measured | Only Step 3.7 Flash measured |
| Neither model has a result on the other 1 board here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index11
| Benchmark | Step 3.7 Flash | Solar Pro 3 | Leader |
|---|---|---|---|
| IFBench | 67.3% | 71.2% | Solar Pro 3 |
| Long context reasoning (AA-LCR) | 73.7% | 32.3% | Step 3.7 Flash |
| Neither model has a result on the other 44 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Step 3.7 Flash | Solar Pro 3 | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Solar Pro 3 costs less
Repository review
50K input + 3K output tokens
Solar Pro 3 costs less
Agent loop
200K input + 10K output tokens
Solar Pro 3 costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | StepFun Step 3.7 Flash | Upstage Solar Pro 3 |
|---|---|---|
| Maker | StepFun | Upstage |
| Weights | Open weights | No public weights listed |
| Released | May 28, 2026 | January 27, 2026 |
| Context window | 262K | 131K |
| Input $/Mtok | $0.20 | $0.15 |
| Output $/Mtok | $1.15 | $0.60 |
| Coding index | Not benchmarked | Not benchmarked |
| Independent measurements behind it | 0 | 0 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Step 3.7 Flash better than Solar Pro 3 for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. Pick Step 3.7 Flash for a larger context window (262K against 131K tokens) and work measured by IFBench, where it leads.
Which is cheaper, Step 3.7 Flash or Solar Pro 3?
Step 3.7 Flash costs $0.20 per million input tokens and $1.15 per million output tokens; Solar Pro 3 costs $0.15 and $0.60. Cost per solved task is known for neither of them.
Which has the bigger context window, Step 3.7 Flash or Solar Pro 3?
Step 3.7 Flash, with 262K tokens against 131K.
How many benchmarks is the Step 3.7 Flash vs Solar Pro 3 comparison based on?
9 benchmarks have a result for both models as of October 21, 2026. Step 3.7 Flash's coding index rests on 0 independent benchmarks and Solar Pro 3's on 0. Where only one model has a result, the page says so instead of naming a winner.